The invention relates to a profiled web for arrangement between the underside of floor tiles, such as ceramic tiles or the like, to be laid on a support plate in a thin retaining layer and the upper surface of the support plate comprising an inherently rigid plastic film which is so profiled by closely spaced, parallel, strip-shaped successive sections, which are so deformed, preferably turned over or folded, in the opposite sense to the preceding strip-shaped section, that channels are produced which are open alternately to the support plate and to the underside of the floor tiles.
The upper surface of the substrates of balconies or terraces subjected to atmospheric influences, i.e. in general concrete support plates, which are to be laid with tiles, preferably ceramic tiles, are increasingly sealed by means of sealing slurries or so-called liquid films. Spaces in the thin mortar layer beneath the ceramic lining cannot be precluded. If leaking water flows into the spaces via the joints in the tile covering frost spalling frequently occurs on glazed ceramic tiles. Furthermore, water trapped in such spaces expands so that the ice which forms results in the ceramic tile covering being cracked away from the thin retaining mortar layer.